var isAppOn = false;
chrome.browserAction.onClicked.addListener(function(tab) {
	isAppOn = !isAppOn;
	var contentScript;
	if(isAppOn){
		contentScript = "content_script.js";
	}else{
		contentScript = "content_script_off.js";
	}
	chrome.tabs.executeScript(null, {file: contentScript});
});